Mu-Tron III

Beigel said he chose the envelope-controlled filter over other synthesizer elements, such as ring modulation, because it sounded more musical; it was a more general effect that would lend itself to a variety of applications, and it was easy to use.

[citation needed] The Mu-tron III was an instant success and was used by jazz/fusion guitarist Larry Coryell,[2] Funkadelic bass player Bootsy Collins (for his "Space Bass"), guitarist Jerry Garcia,[3] Yes bassist Chris Squire, and Stevie Wonder,[2] who used it on his Clavinet for the song "Higher Ground".

Musitronics licensed the Mu-tron III circuitry to a few different companies in the seventies – the Univox Funky Filter and Monacor Effectmatic are notable examples.

Michael Dregni, in Vintage Guitar, noted that none of the "clones, copycats, and other attempts to bring it back...sounded quite like the real deal".

[1] It also has an internal potentiometer which allows the user to adjust the envelope filter's response time to match the player's style.